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Biomedical subjects

D Petrie

Publications and source records attributed to D Petrie.

14 recordsLinked to original sources
PubMed2003

Complications following management of displaced intra-articular calcaneal fractures: a prospective randomized trial comparing open reduction internal fixation with nonoperative management.

OBJECTIVE: To report on all complications experienced by patients with displaced intra-articular calcaneal fractures (DIACFs) following nonoperative management or open reduction internal fixation (ORIF). DESIGN: Prospective, randomized, multicenter study. SETTING: Four level I trauma centers. PATIENTS: The patient population consisted of consecutive patients, age 17 to 65 at the time of injury, presenting to 1 of the centers with DIACFs between April 1991 and December 1998. INTERVENTIONS: Patients were randomized to the nonoperative treatment group or to operative reduction using a lateral approach to the calcaneus. MAIN OUTCOME MEASUREMENTS: Follow-up for patients was at 2 weeks, 6 weeks, 3 months, 12 months, 24 months, and once greater than 24 months following injury. At each follow-up interval, patients were assessed for the development of major and minor complications. After a minimum of 2-year follow-up, patients were asked to fill out a validated visual analogue scale questionnaire (VAS) and a general health review (SF-36). RESULTS: There were 226 DIACFs (206 patients) in the ORIF group with 57 of 226 (25%) fractures (57 of 206 patients [28%]) having at least 1 major complication. Of 233 fractures (218 patients) nonoperatively managed, 42 (18%) (42 of 218 patients [19%]) developed at least 1 major complication (indirectly resulting in surgery). CONCLUSION: Complications occur regardless of the management strategy chosen for DIACFs and despite management by experienced surgeons. Complications are a cause of significant morbidity for patients. Outcome scores in this study tend to support ORIF for calcaneal fractures. However, ORIF patients are more likely to develop complications. Certain patient populations (WCB and Sanders type IV) developed a high incidence of complications regardless of the management strategy chosen.

Adolescent↗
PubMed2000

A randomized controlled trial on the effect of educational interventions in promoting airway management skill maintenance.

STUDY OBJECTIVE: This study was conducted to determine the natural history of airway management skill decay and examine the effect of independent practice and periodic feedback on airway management skill maintenance. METHODS: This prospective, randomized controlled study conducted at Dalhousie University in Halifax, Nova Scotia, Canada, between November 1997 and September 1998. A convenience sample of 84 health sciences students with no prior airway management experience was used. Participants were trained using an advanced airway manikin and then were randomly assigned to control (n=24), periodic feedback only (n=30), and independent practice plus periodic feedback (n=30) groups. Performance was measured by a 52-point weighted checklist at 0, 16, 25, and 40 weeks after the initial program. RESULTS: Group scores were analyzed using a mixed-model repeated-measures analysis of variance and Bonferroni-adjusted P values. Overall group (P =.0002) and time (P =.0001) effects were significant. At time 0, there was no statistical difference in mean scores between groups (range 45.0 to 45.2). Control group performance fell over the first time interval (0 to 16 weeks) (mean score=34.0, P =.002) and remained lower at all intervals without further significant change. Scores in the independent practice plus feedback group revealed no significant changes over time and were significantly higher than the control group throughout. Performance in the periodic feedback only group showed a nonsignificant trend to improved performance over the control group. CONCLUSION: Airway management skill performance declines early after initial training. Independent practice combined with periodic feedback was effective in maintaining performance scores in an advanced airway management simulation. Periodic evaluation with feedback alone showed a nonsignificant trend toward improvement over control.

Airway Obstruction↗
PubMed1999

Sympathetic response to stimulation of the pontine A5 region in conscious rabbits.

Studies in anaesthetized animals have shown that the pontine A5 noradrenergic region plays an important role in the sympathetic control of arterial pressure (AP). The aim of this study was to develop, in conscious rabbits, a technique for microinjections into the A5 region and examine the effects of stimulation of this region on renal sympathetic nerve activity (RSNA). In preliminary mapping experiments on four anaesthetized rabbits, electrical stimulation of the A5 region induced a pressor response ranging between 25 and 75 mmHg while unilateral injection of glutamate (100 nmol) did not change AP. The mapping experiments were used to enable guide cannulae implantation for subsequent microinjections into the A5 region. In six conscious rabbits, unilateral injection of glutamate (100 nmol) caused a consistent increase in RSNA (+45%) but did not change AP. In another eight rabbits, bilateral injection of glutamate (0.3, 3, 30 nmol) into the A5 region dose-dependently increased RSNA by 13%, 30% and 40%, respectively. In four rabbits, angiotensin II (0.3, 3, 30 pmol) injected bilaterally into the A5 region increased RSNA by 5%, 22% and 28%, respectively. In all animals the increase in RSNA was mainly mediated by increasing amplitude of sympathetic synchronized bursts while their frequency remained unchanged. However, both glutamate and angiotensin II did not change AP indicating that the sympathoexcitatory response to the A5 stimulation might be relatively confined to the renal bed. Using a novel microinjection technique developed for conscious rabbits, we found that the A5 region may provide an important excitatory and possibly selective input to the renal sympathetic preganglionic neurons.

Angiotensin II↗
PubMed1998

Accuracy of screening compression ultrasonography and clinical examination for the diagnosis of deep vein thrombosis after total hip or knee arthroplasty.

OBJECTIVE: To determine whether compression ultrasonography or clinical examination should be considered as screening tests for the diagnosis of deep vein thrombosis (DVT) after total hip or knee arthroplasty in patients receiving warfarin prophylaxis postoperatively. DESIGN: A prospective cohort study. SETTING: A single tertiary care orthopedic centre. PATIENTS: One hundred and eleven patients who underwent elective total hip or knee arthroplasty were enrolled. Postoperatively the warfarin dose was adjusted daily to maintain the international normalized ratio between 1.8 and 2.5. Eighty-six patients successfully completed the study protocol. INTERVENTION: Before they were discharged from hospital, patients were assessed for DVT by clinical examination, bilateral compression ultrasonography of the proximal venous system and bilateral contrast venography. RESULTS: DVT was found in 29 patients (34%; 95% confidence interval [CI] 24% to 45%), and 6 patients (7%; 95% CI 3% to 15%) had proximal DVT. DVT developed in 18 (40%) of 45 patients who underwent total knee arthroplasty and in 11 (27%) of 41 patients who underwent total hip arthroplasty. The sensitivity of compression ultrasonography for the diagnosis of proximal DVT was 83% (95% CI 36% to 99%) and the specificity was 98% (95% CI 91% to 99%). The positive predictive value of compression ultrasonography was 71%. In contrast, clinical examination for DVT had a sensitivity of 11% (95% CI 2% to 28%) and a positive predictive value of 25%. CONCLUSIONS: DVT is a common complication after total hip or knee arthroplasty. Compression ultrasonography appears to be a relatively accurate noninvasive test for diagnosing postoperative proximal DVT. In contrast, clinical examination is a very insensitive test. Whether routine use of screening compression ultrasonography will reduce the morbidity of venous thromboembolism after joint arthroplasty requires confirmation in a prospective trial involving long-term follow-up of patients.

Aged↗
PubMed1997

Ultrasonographic screening before hospital discharge for deep venous thrombosis after arthroplasty: the post-arthroplasty screening study. A randomized, controlled trial.

BACKGROUND: The clinical significance of asymptomatic deep venous thrombosis that develops after joint arthroplasty and the value of screening tests to detect thrombi are uncertain. OBJECTIVES: To determine 1) the rate of symptomatic deep venous thrombosis or pulmonary embolism occurring after hospitalization for joint arthroplasty and 2) the value of screening compression ultrasonography. DESIGN: Double-blind, randomized, controlled trial. SETTING: Tertiary care hospital. PATIENTS: 1024 patients undergoing elective total hip or knee arthroplasty who received warfarin prophylaxis. INTERVENTION: Patients were randomly assigned to undergo either bilateral compression ultrasonography or a sham procedure before hospital discharge. Patients with a diagnosis of asymptomatic deep venous thrombosis were treated after discharge with standard anticoagulant therapy; other patients had warfarin therapy discontinued at discharge. All patients were followed for 90 days. RESULTS: In the screening group, asymptomatic proximal deep venous thrombosis was detected in 13 of 518 patients (2.5%). Another 4 patients subsequently developed symptomatic proximal deep venous thrombosis, and 1 patient treated for asymptomatic deep venous thrombosis developed major bleeding, for a total outcome event rate of 1.0% (5 of 518 patients). In the placebo group, 3 patients developed symptomatic proximal deep venous thrombosis and 2 had nonfatal pulmonary embolism, for a total event rate of 1.0% (5 of 506 patients) (difference, 0 percentage points [95% CI, -1.2 to 1.2 percentage points]). CONCLUSIONS: In patients undergoing total hip or knee arthroplasty, the use of warfarin prophylaxis during hospitalization results in a very low rate of symptomatic deep venous thrombosis or pulmonary embolism after hospital discharge. The use of screening compression ultrasonography at hospital discharge does not seem to be justified in this setting.

Algorithms↗
PubMed1996

Effect of proximal and distal venting during intramedullary nailing.

During intramedullary manipulation, 2 main phenomena occur. A dramatic rise in intramedullary pressure occurs followed by intravasation of damaged marrow tissue. There are concerns about the development of increased interosseous pressure during reaming and the potential for this to contribute to fat embolism syndrome. The intramedullary pressures generated with various intramedullary devices was determined and the effects of a fracture, with and without proximal and distal venting on these pressures were studied. Pressures generated in 78 embalmed anatomic specimen femurs and tibias were studied, leaving all soft tissues intact. Pressures were recorded for awl, guide rod, reamer, and nail insertion. Venting was done by creating a 4.5-mm hole in the cortex directly opposite the transducer. Proximal venting reduced proximal pressures to 80 mm Hg in the tibia (90% reduction) and 460 mm Hg in the femur (70% reduction). Distal venting reduced distal pressures to 65 mm and 30 mm in the tibias and femurs, respectively (90% reduction in pressures). Intramedullary pressures generated during nail or alignment rod insertion in anatomic specimen bone greatly exceeds the critical thresholds (150 mm Hg) thought to be responsible for fat emboli to the lung in the dogs. The introduction of a vent may reduce the chance of fat embolism. Despite the high association of raised intramedullary pressures and fat emboli in animal studies, there is no known critical threshold for humans. Therefore, although venting seems effective in reducing the intramedullary pressure in anatomic specimen bones, its efficacy in the patient with trauma remains to be determined.

Biomechanical Phenomena↗
PubMed1996

An evaluation of patient outcomes comparing trauma team activated versus trauma team not activated using TRISS analysis. Trauma and Injury Severity Score.

OBJECTIVE: The purpose of this study was to compare the outcomes of trauma patients with an Injury Severity Score (ISS) > 12 who had the trauma team involved (TTA) in their resuscitative care to those that did not (TTNA). SETTING: Level I regional trauma center teaching hospital with university affiliation. METHODS: All trauma patients admitted between July 1, 1991 and August 31, 1994 with an ISS > 12 were identified through the trauma registry. Burn patients, those who suffered their injury > 24 hours before admission, and deaths in the emergency room were excluded from analysis. The TRISS methodology, which offers a standard approval for evaluating outcomes for different populations of trauma patients, was used to determine whether there was a difference in outcomes between the two groups. To include patients who arrived at the trauma center intubated, a Trauma and Injury Severity Score (TRISS)-like analysis was also conducted on this patient population. MAIN RESULTS: A total of 640 patients were identified; 174 (65.2%) in the TTA group and 223 (34.8%) in the TTNA group. A total of 448 (70%) were eligible for TRISS analysis and 574 (89.7%) were eligible for TRISS-like analysis. Using the TRISS analysis, the TTA group had a Z statistic of 3.36 yielding a W score of 4.27. This compared to the TTNA group whose Z statistic was 0.30. Using the TRISS-like logistic regression equation, the TTA group had a Z statistic of 6.50, yielding a W score of 8.60 compared with the TTNA group whose Z statistic was 0.88. After controlling for differences in the demographics of the two groups, the TTA still had consistently higher Z scores. CONCLUSION: In a Level I trauma center, the outcomes of trauma patients with an ISS > 12 are statistically significantly better if the trauma team is activated than if the patients are managed on an individual service-by-service basis.

Adult↗
PubMed1996

Prescribing exercise for your patient.

The lack of exercise by most Americans is a major contributing factor to many chronic diseases. Physicians are now prescribing exercise for patients just as they would drugs. Compliance with any exercise program depends on realizing the needs and goals of the individual. The fundamental principles of an exercise prescription apply to all persons regardless of age, sex, or level of fitness. A systematic manipulation of the components of frequency, duration, intensity, and progression with periodic reevaluation allows the program to be individualized. The guidelines for the program should include all of the components of health-related physical fitness. These include cardiorespiratory endurance, body composition, muscular strength and endurance, and flexibility. A program for exercise should fit the lifestyle of the patient and be a life-long prescription.

Chronic Disease↗
PubMed1995

Some basic biomechanical characteristics of medullary pressure generation during reaming of the femur.

We measured femoral intramedullary pressures and applied axial thrust force generated in vitro during reaming with the AO and Zimmer systems. Six pairs of cadaver femora were instrumented with pressure taps midshaft and in the distal diaphysis, a load cell distally to measure force, and a displacement transducer to monitor reamer position. Following initial hand reaming, intramedullary power reaming was conducted utilizing a 9-mm reamer initially, with subsequent increases in steps of 0.5 mm. All femora were maintained at 37 degrees C and albumin was used to maintain a fluid-filled canal. The highest pressures consistently occurred during initial power reaming, with peak pressures ranging from 270 to 1500 mmHg amongst femora with the AO system. No significant differences were found in the peak pressures generated for the two systems (P = 0.10). The pressure measurements at the two locations in the femur were consistently similar, indicating that pressures are continuous throughout this aspect of the femur. The pressures were not correlated with instantaneous applied axial thrust (R2 = 0.191), and this could be attributed chiefly to the additional friction force of cutting. While pressure generation in the medullary canal upon reaming is likely governed by the rate of clearance of canal content, this is a highly variable response produced by characteristics of the femur which are still not fully understood.

Aged↗
PubMed1987

Arthrodesis of the wrist.

In a retrospective study, the wrists of 18 patients who underwent arthrodesis by the AO technique were assessed clinically, for hand strength and function. Follow-up averaged 4 years (range from 1 to 7 years). Although wrist arthrodesis improved grip strength, it was still only 50% to 60% of normal. Hand function improved to within normal limits in 78% of patients and bony union occurred in 94.4%. Thirteen patients were back at work within 18 months. The AO technique of wrist arthrodesis allows correction of deformity, relief of pain, increased grip strength and improved hand function.

Arthrodesis↗
PubMed1975

Un-united fracture of the scaphoid.

The anterior approach as described by Matte and Russe for treatment of ununited fractures of the scaphoid was employed in 48 patients using autologous cortical cancellous pegs and chips. Operative intervention occurred in an average period of 14 months after fracture. The average time to radiological union was 3.5 months; the average follow-up was 2 years. Union occurred in 43 patients. The anterior approach is recommended because of its simplicity. Neither avascular necrosis nor a small proximal pole fragment are contraindications to the procedure.

Carpal Bones↗